Iron heating unit



July 28, 1936. J. H. ysTAcKHOUsE 2,049,089

IRON HEATING UNIT Filed Aug. 15, 1934 f l Q ,m/ 7m., JW,

45 Refe lten'ted July 28,' 1936 PArsNroi-FICE IRONYHEATING UNIT John' H. Stackhouse, Chicago, Ill., assigner to Sheridan Electro-Units Corporation, a corporation of Illinois Application August 13. 1934. ySerial No. 739.585 3 Claims. 1- (CL 21S-25) My invention relates to electric irons and more .particularly to a heating element structure for replacing thestandard .heat elements in electric irons or for original use as the heating element of My invention contemplates the provision in a device of this character of a heating unit which may be readily inserted in the iron and which may be inserted with no danger of damage to the heatelement itself.

The standard heating units generally used in electric irons are thin and flat. It is apurpose of my invention to provide a replacement unit which is protected from damage but which is so 155' fconstructed as nott0 have any appreciable increase .in thickness overithe standard heating imit. To this end, my invention contemplates enclosing the :heating element by means of thin L insulating sheets and a sheathof very thin sheet metal.

Furthermore. my invention contemplates the provision of a replacement unit having full protection during the handling` and installation thereof and yet having a highlyemcient heat transferring structure whereby the heat fromv the heating element is transferred to the base of the iron. l

Other features of importance in my invention are the simplicity of structure. the protection ofv'all possible points for short circuit and the protection of the heating wire from oxidation.

I will describe thepreierred form Vof my invention by reference to the accompnyln drawing $5 Fig. 1 is a sectional view illustrating my invention as applied to a standard iron;

llig. 2 is a plan-view illustrating a heating unit constructed in accordance with my invention;

Pig. 3 a sectional view taken on the line 2-3 of Fig.

m. 4 n sectional view teken on me une 4 4 rig.

o. sectional view teken on the vune a-s ng now in detail to the drawing, I show in Fig. an ordinary flat iron of the electrically heatedtypehavingabase I andacover 1.aheating unit` l and a top plate I. The heating element is clamped down against the base l by means 0l of the bolt IIi and nut I I whlchforces the top plate l down in position. The handle for the iron and the attaching means therefor have not been shown lince they form no part oi the` present invention.

Theparts i. l. I and Il are of standard struc- I6 ture but the heating unit embodies the features l, and lower surfaces by the insulating sheets I 9 and 20 which 'preferably are of pure mica. and which as shown clearly in Fig. 3, extend somewhat beyond the edges of the heating element as indicated 15 at 2l and 22. The top .mica sheet I! at the back end where the terminals are connected is cut back as indicated at 22 (see Fig. 5) and the bottom mica' sheet 20 projects out beyond the upturned portions of the terminals I6 and I1 so as 20 to serve as a protection at this point against short circuit being made between the terminals and the iron body.

The terminals when being installed in theiron are suitably protected as for example by apply- 25 ing an insulating sleeve 24 thereo. This sleeve may be of asbestos or similar material. -I The core I2, wire I2 and sheets I9 and 20 all vare placed upon the protecting plaie 25 which is provided with upstanding side flanges such as 26 30 and 21, the center of this plate being slotted as indicated at 2l to accommodate for the bolt I0. The plate 25 thus protects the side edges of the sheets I9 and 20 and also makes a protecting sheath for the lower surface of sheet 20. At the 35 back end of the unit where the terminals i6 and I1 project upwardly the ange 26 is cut away but the edge of theplate 26 extends out almost as far as the mica sheet 2li as shown in Fig. 5.

` A top plate 29 is fitted snugly down between the 40 iianges 26 and 2l over the top of sheet i9 and then the flanges are Abent over and crimped down as indicated at 30 and II in Fig, 3 to grip the side edges of sheets I9 and 20 between the plates 25 and 2t. Plate 29 has a pair of tongues such 45 as 32 and 33 which are struck out of the material thereon and which pass down through suitable openings indicated at 34 in Fig. 4 as provided in the sheets and 2t and the core I2 so as to ilx the position of these elements in the manner to bend downy the nde edeesor this'plateand to is i a certain degree, the side edges oi' the mica sheets so that the heating element is firmly held in position within the sheets Il and 2l. these sheets being cut to exactly tlt the flanges 26 and 21 having no opportunity to shift around.

' The heating unit as assembled above is ready to be placed in the iron in the manner shown in Fig. i. The coverings 25 and 2! are preferably made of a material having a greater heat conductivity than that o! the iron base. In fact we prefer to make them also of a material through which the heat spreads evenly so that when the heating unit is pressed down against the base. the heatfrom the heating element will be evenly distributed to the iron base over the entire bottom surface of the plate 25. I'he high heat conductivity of copper is well known and I prefer to employ this material because of this characteristic and because of its ability to evenly spread the heat.

The success of this unit as a replacement for original heating units that have burned out depends somewhat upon its thickness. If it is too thi-ck, then the cover of the iron cannot be iltted properly. I, therefore, use a very thin material for the sheets 25 and 29. This also facilitates heat transfer to the base of the iron.` The thickness of sheets 25 and 29 should not exceed flve thousandths of an inch per sheet.

From the above description, it is believed that the construction and advantages of this device will be clear to those skilled in this art.

Having thus described one specific form of my invention, what I claim as new and desire to secure by Letters Patent is:

l. A replacement unit for electric irons comprising a fiat core, a resistance element thereon,

protective sheets oi' insulating material on opposite sides oi' the core and having their side edges projecting beyond the core, and a soft metallic cover for said sheets composed of upper and lower plates overlapped and pressed together at their s cover for said sheets composed o! upper and lower l5 y copper plates overlapped and pressed together at their side edges, one of said plates having poaitioning lugs passing through said sheets, said positioning lugs vhaving their free ends bent over between the other of said plates and the adjacent 20 sheet. v

3. A replacement unit for. electric irons comprising a flat core, a resistance element thereon, protective sheets of insulating material on opposite sides of the core, and a soft metallic cover 25 for said sheets composed of upper and lower plates overlapped and pressed together at their side edges, said unit having terminal elements connected to said resistance element and projecting out from said unit, said sheets projecting be- I6 yond the plates at the point where the terminal elements project out, one of said plates having position'ng lugs passing through said sheets, said positioning lugs having their free ends bent over between the other of said plates and the adjacent sheet.

JOHN H. STACKHOUSE.

electric irons coml0 

